Extension bit



Febw 2-, 1926.. 1,571,497

r r G. w. STALEY EXTENSION BIT Filed May 3, 1923 IN V EN TOR.

mmnuuu-mnun A p v Patented Feb. 2, 1926.

UNITED .-STATES GEORGE W. STALEY, OF SAN FRANCISCO, CALIFORNIA.

EXTENSION ."BIT.

Application filed May 3, 1923. Serial No. 636,504. a

To all whom a may concern:

Be it known that I, Gnoncn IV. SrALnY, a citizen of the United States, and a resident of San Francisco county of San Francisco, State of California, have invented a new and useful Extension Bit, of which the following is a specification.

The present invention relates to improvements in extension bits and its particular object is to provide an extension for a bit that may be quickly secured thereto and is firmly held in place. A further object of the invention is to provide means for connecting the extension to the bit that will allow the fastening means to adjust themselves to bits of different sizes. .Further objects and advantages of the device will appear as the specification proceeds.

The preferred forms of my invention are illustrated in the accompanying drawing in which Figure 1 shows a bit attached to my extension, the means for holding the bit being shown in longitudinal section, Figure 2 is a cross section taken along line 1III of Figure 1, Figure 3 is a longitudinal section through a modified form of extension and Figure 4 a cross section through the same taken along line IV-IV of Figure 3. While I have shown only the preferred form of the invention I wish to have it understood that various changes or modifications may be made within the scope of the claim here to attached without departing from the spirit of the invention.

In the form illustrated in Figures 1 and 2 the extension shank (1) provided at one end with a head (2) adapted to be engaged by a brace or a. similar tool not shown in the drawing terminates at its front end in an enlarged portion (3) reduced to substantially semi-circular cross section which however gradually increases toward the end as indicated by the sweeping line (4). Near the end of the substantially semi-cylindrical body thus formed I provide a recess (6) in the base of the same adapted to form a seat or bed for the tapered head (7) of the bit (8). which latter head is of angular cross section and increases in size toward the shank (9) of the bit so as to form a shoulder (11) with the same. A seat formed in the semi-cylindrical body (3) is shaped to follow the outlines of the head (7) of the bit (3) and an annular projection (12) is adapt ed to engage the shoulder (1.1) so as to hold the same against longitudinal displacement.

To look the head of the bit (8) in place within its seat I provide a sleeve (13) which is slidable-on theshank (1) aswell as on the enlarged semi-cylindrical body (3). This sleeve is provided on its inside with a block (14) secured thereto by means of a pin (16) which block is shaped internally to form a complement to the seat (6) so that when the block is in the holding position shown in Figure 1 the block and the seat firmly engage with the faces of the head (7 of the bit When the sleeve (13) is withdrawn by sliding the same downwardly on the shank (1) the block (14) recedes into the substantially semi-cylindrical chamber (17) formed between the sleeve and the semi-cylindrical body portion (3) of the shank (1).

To hold the sleeve (13) in its active position I provide a spacing member (18) and a sleeve nut (19) threadedly engaging the shank (1) as shown at (21).

The manner of attaching the extension to the bit will be readily understood from the foregoing description. The sleeve nut (19) is screwed downwardly which allows the spacing member (18) and the sleeve (13) to drop on the shank The far end of the semi-cylindrical body portion (3) of the shank (1) is thereby cleared of the sleeve and the seat or bed (6) exposed so that the head (7) of the bit (8) may be placed into the same laterally. Holding the'bit and the extension in this position the operator pushes the sleeve (13) upward when the block (14) will engage the free faces of the head (7 and firmly secure the head between the seat 6) and the block (14). The spacer (18) is then pushed upwardly against the sleeve (13) and the sleeve nut (19) advanced on the shank until it holds the sleeve and the spacing member in place.

The form shown in Figures 3 and 4 differs slightly from that shown in Figure 1 in the fact that the seat or bed (6) formed in the body portion (3) of the shank 1) is split longitudinally as shown at (22) which allows the device to adjust itself to hit heads of different sized cross sections. A further difference is shown in the fact that the sleeve (23) is tapered as distinguished from the straight outlines of the sleeve (13) which offers an advantage in so far as it facilitates the withdrawal of the whole device through a hole previously drilled which is in alinement with the hole drilled during iii) the last operation, a situation which frequently occurs for instance in preparinga house for electric wiring where holes may have to be drilled through various members arranged at a distance from one another.

I claim:

An extension for a bit having a shank and a tapered head forming a shoulder-therewith, comprising an extension shank reduced in cross-section near its end having a groove therein forming a bed for the bit head with a shoulder at the front end encircling onehalf of the bit shank and wings forming a continuation of said shoulder and with said shoulder providing a support for the bit head so as to allow the latter to be freely suspended from the extension shank by its shoulder while the bit head is seated and a sleeve slid-able on the extension shank having a block secured thereto engaging the exposed faces of the seated head for firmly locking the same when the sleeve is slidi orwardly.

GEORGE XV. STAL'IG Y. 

